Most Helpful Guy
Most Helpful Girl
I had been in this position :( cheerup!
From my experience, there is maybe 2 answer for this :
1. Maybe he just got bored and want to find other girl. But on the other side he still want to be with you, thats why he still keep your contact in case he didn't get the new one and miss you.
2. Or maybe he thought its nothing, its already end for him. he didn't feel anything anymore so having your phone number is not his concern. He just doesn't care.
Just a suggestion from me, if you still love him and thought he is the one, try to contact him again. But actually there is still lot of good guy deserve you.